A description is given of the installation which was constructed at an altitude of 3 200 m for the study of nuclear interactions at energies of 1012–1013 eV. The apparatus, which has an effective area of 10 m2, includes an ionization calorimeter and a Cerenkov total absorption spectrometer for the measurement of the energies of the primary particles, a μ-meson detector consisting of Cerenkov counters and spark chambers, and also a spark chamber for the study of the angular distribution of secondary particles.